praseodymium

/ˌpreɪzɪəʊˈdɪmɪəm/

noun

1.

a malleable ductile silvery-white element of the lanthanide series of metals. It occurs principally in monazite and bastnaesite and is used with other rare earths in carbon-arc lights and as a pigment in glass. Symbol: Pr; atomic no: 59; atomic wt: 140.90765; valency: 3; relative density: 6.773; melting pt: 931°C; boiling pt: 3520°C

rare metallic element, 1885, coined in Modern Latin by discoverer Carl Auer von Welsbach (1858-1929) from Greek prasios "leek-green" (from prason "leek") + didymos "double," the name given to an earth in 1840, so called because it was a "twin" to lanthana. When didymia was further analyzed in the 1880s, it was found to have several components, one of which was characterized by green salts and named accordingly, with the elemental suffix -ium.

(prā'zē-ō-dĭm'ē-əm) Symbol PrA soft, malleable, silvery metallic element of the lanthanide series that develops a green tarnish in air. It is used to add a yellow tint to glass and ceramics and to make the glass used in welding goggles. Atomic number 59; atomic weight 140.908; melting point 935°C; boiling point 3,127°C; specific gravity 6.8; valence 3, 4. See Periodic Table.